Turbine vane repairing method

Abstract

In a turbine vane repairing method, a damaged spot removing step of removing a damaged spot in one shroud of two shrouds, a member disposing step of disposing a deformation curbing member which comes into contact with each of the two shrouds and curbs change in relative positions between the two shrouds, an overlay welding step of performing overlay welding with respect to a removed part from which the damaged spot is removed in the one shroud and filling the removed part after the damaged spot removing step and the member disposing step, a member detaching step of detaching the deformation curbing member from the turbine vane after the overlay welding step, and a finishing step of polishing at least a surface of a part subjected to the overlay welding in the one shroud are executed.

What is claimed is: 
     
       1. A turbine vane repairing method for repairing a damaged spot in a first shroud of an outer shroud and an inner shroud in a turbine vane having a blade body which has a cross section forming a blade profile and extends in a blade height direction perpendicular to the cross section, the outer shroud being provided at an end of the blade body on a first side in the blade height direction, and the inner shroud being provided at an end of the blade body on a second side in the blade height direction, the turbine vane repairing method comprising:
 removing the damaged spot in the first shroud; 
 disposing a deformation curbing member which comes into contact with the outer shroud and the inner shroud and curbs change in relative positions of the outer shroud and the inner shroud; 
 performing overlay welding with respect to a removed part from which the damaged spot is removed in the first shroud and filling the removed part after the removing of the damaged spot and the disposing of the deformation curbing member; 
 detaching the deformation curbing member from the turbine vane after performing the overlay welding; and 
 polishing at least a surface of a part subjected to the overlay welding in the first shroud. 
 
     
     
       2. The turbine vane repairing method according to  claim 1 ,
 wherein the deformation curbing member has a strut having a first end and a second end, and 
 wherein, during the disposing of the deformation curbing member, a first end of a strut is fixed to a part excluding the damaged spot in the first shroud, and a second end of the strut is fixed to a second shroud of the outer shroud and the inner shroud. 
 
     
     
       3. The turbine vane repairing method according to  claim 2 ,
 wherein the strut is a first strut having the first end and the second end, and the turbine vane further comprises a second strut having a first end and a second end, and 
 wherein, during the disposing of the deformation curbing member, the first end of the first strut and the first end of the second strut are fixed to the first shroud, and the second end of the first strut and the second end of the second strut are fixed to the second shroud such that the removed part in the first shroud is positioned between the first strut and the second strut. 
 
     
     
       4. The turbine vane repairing method according to  claim 3 ,
 wherein the deformation curbing member comprises a beam having a first end fixed to the first strut and a second end fixed to the second strut, and 
 wherein, during the disposing of the deformation curbing member, the first strut and the second strut are coupled by the beam by fixing the first end of the beam to the first strut and fixing the second end of the beam to the second strut. 
 
     
     
       5. The turbine vane repairing method according to  claim 4 , wherein, during the disposing of the deformation curbing member, the first end of the beam is welding-joined to the first strut and the second end of the beam is welding-joined to the second strut. 
     
     
       6. The turbine vane repairing method according to  claim 2 , wherein, during the disposing of the deformation curbing member, the first end of the strut is welding-joined to the first shroud and the second end of the strut is welding-joined to the second shroud. 
     
     
       7. The turbine vane repairing method according to  claim 1 ,
 wherein both the outer shroud and the inner shroud have a gas passing surface facing a side where the blade body is present in the blade height direction and a counter gas passing surface having a back-to-back relationship with the gas passing surface, and 
 wherein, when the removed part in the first shroud penetrates the first shroud from a part on the gas passing surface of the first shroud to a part on the counter gas passing surface of the first shroud, the overlay welding is performed with respect to the removed part from a side of the counter gas passing surface by bringing a patch plate formed of copper or brass into contact with the gas passing surface of the first shroud. 
 
     
     
       8. The turbine vane repairing method according to  claim 1 , further comprising performing heat treatment for reducing welding residual stress occurring due to overlay welding with respect to the turbine vane after the overlay welding step and before the detaching of the deformation curbing member from the turbine vane. 
     
     
       9. The turbine vane repairing method according to  claim 8 , wherein a material for forming the deformation curbing member is identical to a base material of the turbine vane.